Just read through the forum, and would like to comment on some of the things discussed;
1. Dungeon ideas (page 3, by dullman)
-- Maybe instead of having dungeons reset, dungeons can appear and disappear depending on time, and if you took/destroyed/whatever the 'core' (the core could be a boss or something.
-- In the old WM, I got a feeling that dungeons were kinda a portal to another world, so what you were doing was raiding places there, eg something like Gate: Thus the JSDF Fought There (it's a novel, but has a manga adaption)
2. Ways to get girls.
-- Building: Cyborg, Android, Homunculus, etc
-- Depending on laws and such, raiding villages/tribes/etc, joining wars, etc
3. Not sure what to call this, but uhh, Empire(?) & royalties/nobles(page 4, by Romanul); there are some ways you could go about this.
-- Take my example on portals to another world for example, you could raid other worlds and capture their royalties and such.
-- There was also my point on joining wars.
-- Or you could bribe people to kidnap, and sell, you royalties/nobles, this was you legally own them, but the process wasn't so 'legal'.
These to are way too ambiguous/ambitious
-- Also, maybe once you get enough 'power' you can try to take over, and go full world conquest XD (Could be tied to 'New Game+')
-- There is also the whole dungeon master idea.
4. Rooms and capacity. (page 4, by dullman)
-- Hmm, yeah rooms, and beds, should only be big enough for X amount of people at a time, and with the whole building, where they can only provide for X amount of people, due to time and such, makes it more realistic.
5. Jobs depending on buildings (same as 4)
-- I'm thinking this suggestion came from Sibr1x, where depending on what type of building you have (like kitchen, bar, gambling den, dungeon, etc), there are more options for what girls can do.
6. Pregnancy & Child rearing/raising (page 4-5)
-- So, you have a room that speeds up time, but no potion that accelerations/reverse age/body growth? I'm pretty sure it's possible, since I've read stuff online about it all being in the hormones produced, and there are even animals (jellyfish mainly) that can do this. Though if you you use the item, there might be more drawbacks, like mind of a child (naive, and such), but it'd allow quicker 'usage'.
7. Genetics (page 6)
-- This is pretty neat, and there are quite a few games with this, an example is breeding season.
-- Anyways, I'd probably say it's harder then it looks, as you'll have to set up 'profiles' for all the male costumers as well (idea came from succubus brothel)
-- Also, there are regular games, which uses... what was it called... well, you know that two by two chart you studied in biology. Anyways, pretty much each 'parent' has a pair for each 'trait', and there are dominate and recessives :p
Anyways, here's a new idea: New Game+. Pretty much, restarting the game with bonuses, could be anything: such as points to spend on bonuses (think selection of background and traits); depending on what you do/how you play, gain stuff; etc
Ps. Had it written better, but stupid wifi disconnected so it was lost :'C